1. Field of the Invention
The present invention is directed to icons and similar types of graphical objects that are employed in a graphical user interfaces for computers, and more specifically to a method and apparatus which is able to substitute icon images for one another in order to change the appearance of a graphical user interface.
2. Description of the Related Art
Conventional graphical user interfaces make extensive use of icons within a computer display system. Graphical icons used on display screens in computer systems can represent disks, documents and other computer applications selected by a user, in order to utilize the element(s) represented by the graphical icon. Besides accessing computer applications and documents, icons can be manually manipulated by a user to perform tasks easily. For example, an icon representing a word processing document can be selected by a mouse that is manipulated by a user, and be either placed onto another icon representing a word processing application or placed onto an icon of a printer which represents a printing application. Once placed on the printer icon or word processor icon, the document is printed or opened by the word processor, respectively.
To permit users to personalize the graphical user interface, some conventional systems enable the user to both create and modify graphical icons for a variety of purposes. For example, facial features such as hair color, skin color and hair style of an icon image representing a human face can be edited.
Many different icons can be employed within a computer system to graphically represent the presence of different applications and documents. Many of these icons are only changed slightly with respect to their appearance. An icon image can also change depending upon the status of the document or how the document is currently being employed with the computer system. For example, a document may have one icon image when it is not being used, and another slightly different icon that represents an alias of the same document. Also, a document may have been "locked" by a user, may be currently accessible on a network, or may be in use on the network by another user. Currently, software programmers, when developing the user interface, must utilize valuable time and resources in order to design individual icons for each of the situations that could arise in the operation of the computer system.
Another situation which requires the allocation of resources is a change in the icon image after the original icons have been stored in a computer system. For instance, user interfaces have been proposed which permit the user to switch between different appearances, or themes. Each theme can have its own design for various objects such as windows, menus and icons. For example, the graphical icon images used in a system for a child might differ from those for an adult, or the graphical icon images used in a system for a business might differ from those for a non-business use. Another theme could involve showing each icon as a 3-dimensional image rather than a 2-dimensional image. When performing a change between different themes, the graphical user interface must determine the new icon image that is required by the switch in themes, and thereafter retrieve and display the icon image for the new theme. This could require an appreciable amount of processing and occupy time that the processor could be using to perform other tasks. Therefore, the icons need to be able to be quickly referenced and displayed even if a theme change, with respect to all icons, has taken place.
Many icons representing the different attributes of applications and documents can be required in order for a computer to properly depict, through icons, system status. The time consuming labor required to create such icons increases the cost of the system. Also, memory is consumed by the storage of icon image data, some of which are rarely used. Therefore, the need exists to reduce the amount of design effort and memory storage involved with icons while maintaining or increasing the ability for icons to accurately represent documents, applications, etc. Also, a need exists to reduce the amount of processing time allocated to changing icon images from one representation to another.